maths identites Flashcards
1
Q
(a + b)^2
A
a^2 + 2ab + b^2
2
Q
(a – b)^2
A
a^2 – 2ab + b^2
(a+b)^2 - 4ab
3
Q
a^2 – b^2
A
(a + b)(a – b)
4
Q
(x + a)(x + b)
A
x^2 + (a + b) x + ab
5
Q
(a + b + c)^2
A
a^2 + b^2 + c^2 + 2ab + 2bc + 2ca
6
Q
(a + b)^3
A
a^3 + b^3 + 3ab (a + b)
7
Q
(a – b)^3
A
a^3 – b^3 – 3ab (a – b)
8
Q
a^3 + b^3 + c^3 – 3abc
A
(a + b + c)(a^2 + b^2 + c^2 – ab – bc – ca)
9
Q
a^3 +b^3
A
(a+b)(a^2 -ab +b^2)
a + b )^3 - 3ab(a+b
10
Q
a^3 -b^3
A
(a-b)(a^2 + ab +b^2)
a - b)^3 + 3ab (a - b
11
Q
y
A
sinθ
12
Q
x
A
cosθ
13
Q
a^2 + b^2
A
(a + b)^2 - 2ab
14
Q
D < 0
A
no real roots
15
Q
D > 0
A
real and distinct
